Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Allowance for accounts receivable and chargebacks	$ 554	$ 455
Preferred Stock, Par Value (usd per share)	$ 0.001	$ 0.001
Preferred Stock, Authorized (in shares)	5,000,000	5,000,000
Preferred Stock Outstanding (in shares)	0	0
Common Stock Par Value (usd per share)	$ 0.001	$ 0.001
Common Stock Authorized (in shares)	5,600,000,000	5,600,000,000
Common Stock Issued (in shares)	1,300,000,000	1,308,000,000
Common Stock Outstanding (in shares)	1,300,000,000	1,308,000,000